1. Field of the Invention
The present invention relates generally to a driving technique, and more particularly to an image-stabilization driving device capable of keeping image quality from being adversely affected by shake.
2. Description of Related Art
Optical systems and actuators applied in mobile phones or cameras have simple structures and small volume due to size limitation.
Along with wide application of mobile phone cameras nowadays, image quality of mobile phone cameras is expected to be same as that of digital cameras. For example, pixel number of mobile phone cameras has increased from 300,000 to 3,000,000. Meanwhile, in order to obtain preferred image quality, traditional fixed focal lens has been replaced by auto focus lens. In addition, optical zoom lens is integrated in mobile phone camera modules to replace digital zoom function that gives poor image quality. However, as mobile phones are light-weight and users generally operate mobile phones by single hand, image quality may usually be degraded by hand shake. Also, hand shake can easily occur when mobile phones are used indoors with poor lightness. Therefore, anti-hand shake mechanism is also needed in future mobile phones.
Although thin-type mobile phone cameras are easy to use, lens blur phenomenon can easily occur because of hand shake, especially when a person continuously takes photos during a long time and has poor hand force and stability. For example, blur image can occur due to tiny shake during zoom lens. Thus, an image-stabilization system is required to be integrated into optical system of thin-type mobile phones or cameras so as to provide anti-hand shake compensation function.
Compensation design for obtaining stabilized image quality has been proposed in such as US Publication Nos. 2003067544, No. 2006056829, U.S. Pat. No. 5,768,016, JP Publication Nos. 2003111444 and No. 2004241922. For example, a smooth impact drive mechanism (SIDM) integrated to a lens module is proposed by WADA etc. in Minolta Corporation, wherein two piezoelectrical actuators are used to control coordinate position (X, Y) of an image sensor in a plane, thereby stabilizing image quality. US Publication No. 20060056829 discloses a smooth impact drive mechanism comprising a stacked three-layer metal frames, which however has complicated components and accordingly has complicated assembly process and cannot meet the requirement of module miniaturization. Moreover, the present optical stabilization systems are mainly aimed at digital cameras and cannot meet requirement of mobile phone cameras.
Therefore, there exists a strong need to provide an image-stabilization driving device that is miniaturized and has simple structure and is easy to fabricate and assemble so as to overcome the above-mentioned drawbacks.